JP2001143065A - Image-processing method and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve the problem where limited observation environment is required to realize sure color matching by CMS. SOLUTION: Each item of observation conditions is set by a user interface to set the observation conditions S102, an observation condition tag and a private tag for scanner and monitor profile are created, based on setting of the items S103, the scanner profile corresponding to set 'white of illumination for observation' and the monitor profile corresponding to the set 'white of a monitor' are selected S104 to S105, the created observation condition tag and the private tag are set in the selected scanner and monitor profiles S106 and color matching is executed S107 to S108.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to image processing, for example, to image processing for performing chromatic adaptation conversion such as color matching according to viewing conditions.

[0002]

2. Description of the Related Art FIG. 1 is a view showing an observation environment (Viewing Condition) in a CMS (Color Management System).
The observation environment is defined by placing a color patch (standard background such as N5) under a fluorescent lamp that reproduces the characteristics of the standard light source D65 and D50, reading the color patch with a scanner, and performing color matching processing. Perform and color the results on a CRT under dark environment (Dark Surround) (standard background such as N5)
Is limited, the color patch and the CRT color are observed in the same color.

As described in Japanese Patent Application Laid-Open No. Hei 7-222009, generally, a color management system
It is composed of an M (Color Management Module) and a device profile (Device Profile), and performs color conversion processing using a profile corresponding to the source device before conversion and a profile corresponding to the destination device after conversion. The former profile is called a source device profile, and the latter profile is called a destination device profile.

FIG. 2 is a diagram showing a CMS process, which shows conversion from a scanner color space (scanner RGB) to a monitor color space (monitor RGB). Scanner profile (Scanner P
rofile) is a source device profile, and a monitor profile (Monitor Profile) is a destination device profile.

[0005] The scanner RGB is a device-independent color space, XYZ, using a scanner profile.
It is converted to color space and then to monitor RGB using the monitor profile. In this case, the XYZ color space is a space that depends on the standard light source (viewing conditions in FIG. 1), and it can be seen that CMS is a process in which viewing conditions are limited.

FIG. 3 is a diagram showing an example of the structure of a device profile.

[0007] The format of the device profile is Int specified by the ICC (International Color Consortium).
er Color Profile Format is used as an industry standard. The profile is divided into a header part (Profile Header) for management, a tag data access part (Tag Table), and a tag data storage part (Tag Data). The header section stores device information indicating which device (for example, monitor) the profile belongs to, CMM information indicating which CMM the profile uses, and the like. The tag data access section contains Tag Data
A pointer for accessing is stored.

[0008] Tag Data is a required tag (Required Tag), optional tag (Optional Tag) and private tag
(Private Tag), and Required Tag is a CMM (for example, Col
This is used by orSync or the default CMM of ICM, and must be prepared. Optional Tag includes Enhanced Color Transformation
, For example, data for processing related to PostScript (R) level 2. The Private Tag stores data used when a third party other than the OS vendor prepares its own CMM (custom CMM) and performs its own processing.

[0009]

FIG. 4 is a diagram showing an observation environment which is quite close to a general office environment. Here is the figure
There is no light booth (Light Booth) as shown in 1,
The environment for viewing the monitor is also under the same lighting as watching the color patches. That is, the actual observation environment (observation conditions) does not match the observation environment (observation conditions) assumed by the CMS as shown in FIG. Therefore, even if the CMS is used, color matching is not always realized in a general office environment as shown in FIG. In other words, in order to realize reliable color matching by CMS, a limited observation environment as shown in FIG. 1 is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide image processing for performing chromatic adaptation conversion under general viewing conditions.

[0011]

The present invention has the following configuration as one means for achieving the above object.

An image processing method according to the present invention is an image processing method for performing chromatic adaptation conversion on input image data in accordance with a viewing condition, wherein the viewing condition is manually input and corresponds to the input viewing condition. Profile processing, and based on the processed profile, perform color matching processing in consideration of input observation conditions.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[System Configuration] FIG. 5 is a diagram showing an example of a system configuration according to an embodiment of the present invention. The system according to the embodiment includes an information processing apparatus 1 such as a personal computer (PC) and a monitor of a CRT or LCD. 2 and a scanner 3. Hereinafter, the information processing apparatus 1 is referred to as a PC main body.

The PC body 1 includes a microprocessor (CPU) and a video memory (VRAM) necessary for information processing such as monitor display and image processing, and provides basic functions necessary for operation of software such as application software. OS 11, utilities such as color matching processing and RAM 12 used as a work area by the OS, an image data storage unit 13 in which image data is stored, a monitor driver 14 for controlling display data when displayed on the monitor 2, a scanner 3
Interface (I / F) 15 for connecting the
CMM16 which is a module for executing color matching processing, scanner utility 17 which is software for reading a document image set in the scanner 3,
A monitor profile storage unit 18 for storing a monitor profile of the monitor 2 and a scanner profile storage unit 19 for storing a scanner profile of the scanner 3 are provided.

The scanner utility 17 is a viewing condition parameter storage unit in which a plurality of viewing condition parameters are stored.
1A, and a tag data generation unit 1B for generating profile Tag data.

For the image data storage unit 13, the monitor profile storage unit 18, the scanner profile storage unit 19, etc., magnetic recording, magneto-optical recording and optical recording media such as a hard disk, MO and DVD-RAM can be used. .

An interface (I / F) 15 for connecting the scanner 3 includes RS232C, RS422, SCSI, GPIB, USB (Univ.
General-purpose interfaces such as IEEE 1394 and IEEE1394 are available. Therefore, as long as the device has these interfaces, an image acquisition device such as a digital camera, a digital video camera, and a film scanner can be connected instead of the scanner 3. When devices other than the scanner 3 are connected, the scanner utility 17 is replaced with a utility corresponding to those devices as necessary. Similarly, the output device is not limited to a monitor, but may be an apparatus such as a color printer or a film recorder.

[Scanner Utility] FIG. 6 is a view showing an example of a user interface (UI) for setting viewing conditions provided by the scanner utility 17. This UI displays the "brightness" and "whiteness" of the observation illumination, and the "brightness" and "whiteness" of the monitor from the three sensitive (human-sensitive) ranks, respectively. There is a setting item to select. The setting of the rank is not limited to three. For example, it is possible to provide an intermediate rank of three ranks and select from five ranks.

FIG. 7 is a diagram showing values representing viewing conditions corresponding to each rank shown in FIG. The “brightness of the observation light” is represented by the absolute tristimulus value X _L Y _L Z _L of the white of the light,
Y _L is the absolute brightness of the illumination. The rank “dark”, “normal”, and “bright” of “brightness of observation illumination” is a value of Y _L of 90.0.
cd / m ^2, corresponding respectively to the three stages of 157.0cd / m ² and 318.0cd / m ²

"White of observation illumination" rank "Slightly yellow"
"Normal" and "Slightly blue" are white F2 (color temperature: 4150K) that looks slightly yellow, D50 (color temperature: 5000K) that looks normal white, and D65 (color temperature: 650) that looks slightly blue.
0K).

The "brightness of the monitor" is represented by an absolute tristimulus value X _M Y _M Z _M of white of the monitor, where Y _M is the absolute brightness of the monitor. "Monitoring of brightness" rank "a little dark,""normal" and "a little light" of the value of Y _M 70.0cd / m ^2, 90.0c
It corresponds to three stages of d / m ² and 110.0 cd / m ² respectively.

The ranks “normal”, “slightly blue” and “blue” of “white on the monitor” are D50 that looks normal white, D65 that looks slightly blue, and D93 that looks blue (color temperature: 9300).
K) corresponds to each of the three stages.

[CMS Processing Considering Ambient Light] FIG. 8 is a diagram showing an example of the CMS processing in the case where environmental light is considered.

In order to perform color matching in consideration of ambient light, it is important to introduce a CAM (Color Appearance Model) into a CMS. CIE CAM9 specified by the CIE (International Commission on Illumination) in May 1997 as a type of CAM
7s, and FIG. 8 shows processing when CIE CAM97s is used.

The scanner RGB data depending on the characteristics of the scanner, for example, the color patch data read by the scanner 3 is first converted into XYZ data (white light of the VC1 illumination) based on the white point of the illumination under the patch observation condition (VC1). Point-dependent), and the forward conversion of CAM using the viewing condition parameters of VC1 as input, JCh (color perception space relative to the reference white of the observation illumination) or QMH (color perception space of the observation illumination) It is converted into an absolute color perception space whose size changes according to the illuminance level. Then, using the monitor viewing condition (VC2) parameters and the like as input, the CAM is converted into XYZ data (depending on the VC2 lighting white point) based on the lighting white point of the viewing condition (VC2) by inverse conversion of CAM. And finally the monitor RGB
(Depending on the characteristics of the monitor).

FIG. 9A is a diagram showing observation condition parameters of the observation environment shown in FIG. 4, and these are input parameters of the CAM.

The luminance factor (Luminance) on the source side (VC1)
Factors) are the relative tristimulus values of the white point of the illumination (Reference Wh).
ite Point) XwYwZw, luminance of the adaptive visual field (value of 20% of the absolute luminance of the adaptive visual field is set) La (Reference Luminance),
And the relative luminance Yb (Relative Luminanc
e).

The luminance factors on the destination side (VC2) are the relative tristimulus values XrwYrwZrw of the white point of the monitor, the monitor luminance under illumination (a value of 20% of the absolute luminance of the adaptive visual field is set), and the monitor display Is the relative luminance Ybr of the background.

The tristimulus values of a color patch (Color Stimulus) correspond to XYZ (VC1) in FIG. Other CIE CAM97s-specific parameters include the ambient influence constant c (Impact of Surround) and the color induction coefficient Nc
(Chromatic Inducation Factor), lightness contrast coefficient FLL (Lightness Contrast Factor), and adaptation coefficient F (Degree of Adaptation) are parameters that can be set in the source (VC1) and the destination (VC2). The values of these parameters change depending on the ambient light as shown in FIG. 9B.

[Viewing Condition Tag]
FIG. 10 is a diagram showing the contents of the viewing condition tag (viewingCondition Tag) included in the optional tag of the Inter Color Profile Format.

[Abosolute XYZ value for illuminant]
The absolute tristimulus values X _L Y of the white illumination shown in FIG.
_L Z _L, and the absolute tristimulus values X _M Y _M Z _M White monitor corresponds. From now on, the relative tristimulus value XwYwZw of the white point of the illumination shown in FIG. 9A, the luminance La of the adaptive visual field, the relative tristimulus value XrwYrwZrw of the white point of the monitor, and the monitor luminance Lar under illumination
Can be requested. `` Abosolute XYZ value for su
There is no such thing in "round". "Illuminant
The “type” matches the observation illumination and the white of the monitor shown in FIG.

From the absolute tristimulus values X _L Y _L Z _{L of the} illumination white,
The conversion of the white point of the illumination to the relative tristimulus values XwYwZw and the adaptation field of view to the luminance La is represented by the following equation. Xw = 100 × x _w / y _w Yw = 100 Zw = (1-x _w -y _w ) × 100 / y _w … (1) La = 20 × Yw / 100 where x _w = X _L / XYZ _L y _w = Y _L / XYZ _L XYZ _L = X _L + Y _L + Z _L

Also, the absolute tristimulus value X _M Y _M of white on the monitor
From Z _M, relative tristimulus values XrwYrwZrw the white point of the monitor, and conversion to the illumination of a monitor brightness Lar is expressed by the following equation. Xrw = 100 × x _rw / y _rw Yrw = 100 Zrw = (1-x _rw -y _rw ) × 100 / y _rw ... (2) La = 20 × Yrw / 100 where x _rw = X _M / XYZ _M y _rw = Y _M / XYZ _M XYZ _M = X _M + Y _M + Z _M

The above equation shows that X _L Y _L Z _L and X _M Y _M Z _M are absolute values of white, XwYwZw and XrwYrwZrw are relative values of white, and La and Lar consists of a definition of 20% of the absolute brightness of white.

[Private Tag] FIG. 11 shows the Inter Color
FIG. 4 is a diagram illustrating content related to viewing conditions included in a private tag of a Profile Format.

“Relative luminance of background” is the relative luminance Yb of the background under illumination and the relative luminance Ybr of the background displayed on the monitor shown in FIG.
d) is the ambient effect constant c shown in FIG.
The `` induction factor '' is replaced by `` Light
`` ness contrast factor '' is the brightness contrast coefficient FLL shown in FIG. 9A, and `` Degree of adaptation '' is
Each of them corresponds to the adaptation coefficient F shown in A.

[Profile Storage Unit] FIG. 12 shows the three scanner profiles corresponding to the observation illumination white shown in FIG. 7 and the three profiles corresponding to the monitor white shown in FIG. This indicates that the information is stored in the profile storage unit 18. In the scanner profile, data to convert from scanner RGB to XYZ depending on the white of the observation illumination,
In the monitor profile, conversion data from XYZ depending on the white of the monitor to monitor RGB is stored.

[Color Matching Process] FIG. 13 shows an original image set on the scanner 3 by the scanner utility 17, and performs a color matching process between the scanner 3 and the monitor 2 in consideration of the observation conditions. 9 is a flowchart showing a series of processing examples for displaying the result on a monitor 2.

In step S100, the scanner utility 17
Is activated, and a UI for setting the observation conditions shown in FIG. 6 is displayed in step S101. In step S102, the rank of each item of the UI for setting the viewing condition is selected. For example,
The “bright” rank is selected in “brightness of observation illumination”.

Next, in step S103, based on the selection result in step S102, the observation condition tag (see FIG. 10) and the private tag (see FIG. 11) for the scanner profile and the monitor profile are converted to the tag data generation unit 1B.
Created by In step S104, a scanner profile corresponding to the selected rank of “white of observation illumination” is selected from three scanner profiles (see FIG. 12) stored in the scanner profile storage unit 19. In step S105, a monitor profile corresponding to the selected “monitor white” rank is selected from the three monitor profiles stored in the monitor profile storage unit 18 (see FIG. 12).

Subsequently, in step S106, step 103
The observation condition tag and the private tag created in step S105 are set in the scanner and monitor profile selected in step S105. The scanner profile and the monitor profile in which the observation condition tag and the private tag are set are transferred (set) to the CMM 16 in step S107.

In step S108, the CMM 16 executes the color matching process. In step S109, the color matching result, that is, the color-matched image is displayed on the monitor 2, and the process ends.

As described above, color matching between the scanner 3 and the monitor 2 can be performed in consideration of the observation environment.

[Setting of Observation Conditions] FIG. 14 is a flowchart showing a detailed example of step S102 in which the rank of each item of the UI for setting the observation conditions is selected.

In step S200, the rank of "brightness of observation illumination" is selected, and in step S201, it is the absolute value of the white tristimulus value of the illumination corresponding to the selected rank of "brightness of observation illumination". The value of X _L Y _L Z _L is selected from the data shown in FIG. 7 and held.

Next, in step S202, the rank of "white of observation illumination" is selected. In step S203, information corresponding to the selected rank of "white of observation illumination" is selected from the data shown in FIG. Set to Lw.

Next, at step S204, "monitor brightness"
Rank is selected in, in step S205, the value of an absolute value is X _M Y _M Y _M of the tristimulus values of white of the monitor corresponding to the rank of the selected "monitor brightness" shown in FIG. 7 Select from data and keep.

Next, in step S206, the rank of "monitor white" is selected. In step S207, information corresponding to the selected rank of "monitor white" is selected from the data shown in FIG. Set and end the process.

As described above, the information or value corresponding to the rank of each item selected by the UI for setting the viewing condition shown in FIG. 6 can be taken out from the viewing condition parameter storage unit 1A. FIG. 14 shows “brightness of observation illumination”.
The example in which the setting is performed in the order of “observation illumination white”, “monitor brightness”, and “monitor white” has been described. Can be omitted.

[Creation of Tag] FIG. 15 is a flowchart showing a detailed example of step S103 for creating an observation condition tag and a private tag for a scanner and a monitor profile.

In step S300, a type descriptor portion of the observation condition tag shown in FIG. 10 is created, and the contents defined in advance for this tag are entered, and step S3 is executed.
Go to 01. In step S301, reservation of the observation condition tag (Res
erved) part.

Next, in step S302, an “Absolute XYZ value for illuminant” portion of the observation condition tag is created, and the tag for the scanner profile is created in step S201.
In the value of the retained X _L Y _L Z _L, the tags for monitor profile put the value of X _M Y _M Y _M that is held in step S205.

Next, in step S303, an “Absolute XYZ value for surround” portion of the viewing condition tag is created,
Since this tag is not used, enter a NULL value.

Next, in step S304, an "Illuminant type" portion of the observation condition tag is created, and the value of Lw held in step S203 is set for the tag for the scanner profile, and the step S207 is set for the tag for the monitor profile. The process is terminated by inputting the value of Mw held in the step.

As described above, it is possible to create an observation condition tag and a private tag for the scanner and the monitor profile based on the observation condition set by the UI for setting the observation condition shown in FIG.

[Setting of Tag] FIG. 16 is a flowchart showing a detailed example of step S106 for setting an observation condition tag and a private tag created for a scanner and a monitor profile.

At step S 400, the selected scanner profile is read into RAM 12. In step S401, RAM12
A viewing condition tag for the created scanner profile is set in the scanner profile read in. In step S402, a private tag for the created scanner profile is set in the scanner profile read into the RAM 12.

Next, in step S403, the selected monitor profile is read into the RAM 12. In step S404, R
Set the observation condition tag for the created monitor profile in the monitor profile read into AM12. In step S405, a private tag for the created monitor profile is set in the monitor profile read into the RAM 12, and the process ends.

As described above, the scanner profile storage unit
For the scanner and the monitor profile temporarily taken out of the RAM 12 from the monitor profile storage unit 19 and the monitor profile storage unit 18, the tube pressure condition tag and the private based on the observation condition set by the UI for setting the observation condition shown in FIG. Tags can be set.

[Color Matching] FIG. 17 is a flowchart showing a detailed example of step S108 for causing the CMM 16 to execute color matching processing.

In step S500, “Absolute XYZ value f” of the observation condition tag is set based on the set scanner profile.
taking out or illuminant value of X _L Y _L Z _L is the content of the ".
At step S501, it calculates the X _W Y _W Z _W and La using equation (1) described above.

Next, in step S502, the content of the private tag, Y, is read from the set scanner profile.
Retrieve the values of b, c, Nc, FLL and F. In step S503, the content of the “Absolute XYZ value forilluminant” of the observation condition tag is set based on the set monitor profile.
Extract the value of X _M Y _M Y _M. In step S504, the above-described expression
XrwYrwZrw and Lar are calculated using (2).

Next, in step S505, Yb, which is the content of the private tag, is read from the set monitor profile.
Retrieve the values of C, Nc, FLL and F. In step S506, the scanner RGB data is converted into XYZ data depending on the observation illumination white using the scanner profile.

Next, in step S507, from step S501
Based on the parameters obtained in S505, the processing of CIE CAM97s is performed to obtain XYZ data depending on the monitor white. Step S
In 508, the XYZ data depending on white of the monitor is converted into RGB data depending on the monitor using the monitor profile, and the process is terminated.

As described above, color matching can be performed by color matching processing using CIE CAM97s using a scanner and a monitor profile in which tags relating to viewing conditions (viewing condition tags and private tags) are set. is there.

[Process of CIE CAM97s] The details of step S507 for performing the process of CIE CAM97s will be described with reference to FIGS. 18 and 19.

FIG. 18 shows the contents of the forward conversion of the color perception model CIE CAM97s, which performs the correction processing (the processing of converting XYZ into JCh or QMH) according to the viewing condition VC1 on the input image in FIG. It is a flowchart shown.

First, in step S660, as the observation condition information of the input image, La which is the luminance of the adaptive visual field (cd / m ² , usually 20% of the white luminance in the adaptive visual field is selected), and the sample under the light source conditions , XwYwZw, which is the relative tristimulus value of white light under the light source condition, and Yb, which is the relative luminance of the background under the light source condition.
Also, based on the type of viewing condition specified in step S680, as the viewing condition information of the input image, in step S670, a constant c of surrounding influence, a color induction coefficient Nc, a brightness contrast coefficient FLL, and a coefficient F of adaptation are set. Is done.

Based on the input image observation condition information set in steps S660 and S670, tristimulus values XYZ indicating the input image
Is processed as follows.

First, XYZ is converted based on Bradford's three primary colors, which are considered as physiological three primary colors of humans, and Bra is converted.
The dford cone response RGB is obtained (S600). Since human vision does not always perfectly adapt to the viewing illuminant, a variable D that indicates the degree of adaptation based on the luminance level and the surrounding conditions (La and F)
Is calculated based on this variable D and XwYwZw, and the RGB is converted to RcGcBc by performing incomplete adaptation processing (S610).

Next, based on the three primary colors of Hunt-Pointer-Estevez, which are considered as the three primary colors of human physiology, RcGc
By converting Bc, a Hun-Pointer-Estevez cone response R'G'B 'is obtained (S620). The adaptation degree is estimated for the R'G'B 'by the stimulus intensity level, and the post-adaptation cone response corresponding to both the sample and white is obtained (S630). Note that step
In S630, the variable FL calculated based on the luminance La
Is used to perform non-linear response compression.

Subsequently, the following processing is performed to determine the correlation with the appearance.

The opponent red-green and yellow-blue response ab is R'a
The hue H is obtained from G'aB'a (S640), and the hue H is obtained from the opposite color response ab and the eccentricity coefficient (S650).

Further, a background induction coefficient n obtained from Yw and the relative luminance Yb of the background is obtained, and the achromatic responses A and A for both the sample and white are obtained using the background induction coefficient n.
w is obtained (S690), the coefficient z obtained from the background induction coefficient n and the lightness contrast coefficient FLL, and the lightness J is obtained based on A, Aw and c (S651), and the saturation S is obtained from the color induction coefficient Nc. The chroma C is obtained from the saturation S and the brightness J (S652), and the brightness J and the white achromatic response Aw
Is obtained from the luminance (S654).

The colorfulness M is obtained from the variable FL and the constant c of the influence of the surroundings (S655).

Inverse Transform FIG. 19 is a flowchart showing the content of the inverse transform of the color perception model CIE CAM97s that performs the correction process (the process of converting JCh or QMH to XYZ) according to the viewing condition VC2 in FIG. is there.

In FIG. 19, H (hue), J (lightness), and C, which are the correlation amounts of the color perception obtained by the processing shown in FIG.
(Chroma) or h (Hue), Q (Brightness), M
From the value of (colorfulness), X′Y′Z ′ which is an XYZ value under output observation conditions corresponding to the tristimulus value XYZ of the sample is obtained. In FIG. 18, to make the figure easier to understand,
In some cases, arrows indicating processes affected by each coefficient are omitted.

First, as the viewing condition information of the output image specified in step S700, in step S701, the luminance of the adaptive visual field (cd / m ² , usually 20% of the white luminance in the adaptive visual field)
Is set), XrwYrwZrw which is the relative tristimulus value of white light under the light source condition, and Ybr which is the relative luminance of the background under the light source condition. Also, based on the type of observation condition specified in step S700, the constant of the influence of the surroundings is set as the observation condition information of the input image in step S702.
c ′, the color induction coefficient Nc ′, the brightness contrast coefficient FLL ′, and the adaptation coefficient F ′ are set.

First, XYZ is converted based on Bradford's three primary colors, which are considered as physiological three primary colors, and a Bradford cone response Rw'Gw'Bw 'to XrwYrwZrw which is a relative tristimulus value of white light is obtained. (S703).

Since human vision is not always perfectly adapted to the viewing illuminant, the brightness level and ambient conditions (Lar and
Based on F ′), a variable D ′ indicating the degree of adaptation is obtained (S704), and a variable P ′ is obtained from the value of Brw (S705). This variable D ',
Rcw'Gcw'Bcw 'is determined based on P' and Rw'Gw'Bw '(S7
06).

Rcw'Gcw'Bcw 'is converted into XYZ based on the three primary colors of Hunt-Pointer-Estevez, a Hunt-Pointer-Estevez cone response is obtained, and a degree of adaptation is estimated based on the stimulus intensity level. Then, a post-adaptive cone response Raw "Gaw" Baw "of white is obtained (S707).

Next, the lightness J is obtained from the luminance Q obtained in step S654 (S708), and the hue angle h of the unique hue is obtained from the hue angle H obtained in step S650 (S709).

Further, the luminance Lar of the adaptive visual field in step S701
A variable FL 'is obtained based on the above (S710), and a chroma C is obtained from FL' and the colorfulness M obtained in step S655 (S711).

Then, a background derivation coefficient n ′ is obtained from Yrw of step S701 and the relative luminance Ybr of the background (S712), and a saturation s ′ is obtained from the chroma C obtained in step S711 and the brightness J obtained in step S708 ( S713). Step S712
The variables Nbb 'and Ncb' are obtained from n 'obtained in (S714), and Nbb'
Then, a white achromatic response Aw 'is obtained from Raw "Gaw" Baw "obtained in step S707 (S715).

Further, a coefficient z ′ is obtained from the brightness contrast coefficient FLL ′ in step S702 (S716), and a constant c ′ of the influence around the step S702, Aw ′ obtained in step S715, and brightness J obtained in step S708. Achromatic response A 'is determined (S71
Five). This A ′, the color induction coefficient Nc ′ of step S702, the step S702
Opposite-color response of red-green from saturation s ′ obtained in 713, h obtained in step S709, Nbb ′ and Ncb ′ obtained in step S714
a ′ is obtained (S716), and the opposite color response b ′ of yellow-blue is obtained from this a ′ and h obtained in step S709 (S717). And a '
And b ′, Nbb ′ obtained in step S714, and A ′ obtained in step S715, the post-adaptive cone response Ra “Ga” Ba ”is obtained (S718).

Next, from the Ra “Ga” Ba ”, Hunt-Pointer-Este
The vez cone R "G" B "is obtained (S719), and the R" G "B" and step S71 are obtained.
Rc'Gc'Bc 'is determined from the variable FL' determined at 0 (S720), and this R
c′Gc′Bc ′, variable D ′ obtained in step S704, step S705
The variable P ′ obtained in step and Rw′Gw′Bw ′ obtained in step S703
To find the Bradford cone response R "G" B "'(S721)
Under output observation conditions corresponding to sample XYZ from R "G" B "
X'Y'Z 'is obtained (S722).

As described above, it is possible to convert the input observation conditions from XYZ to the output observation conditions X'Y'Z 'using CIE CAM97s.

As described above, in accordance with the observation conditions set by the UI for setting the observation conditions shown in FIG. 6, a plurality of scanners and monitor profiles corresponding to the observation conditions of white are prepared, and the CIE CAM97s is processed. By setting a tag, which is necessary information, in a scanner and a monitor profile, it is possible to perform CMS processing compatible with CIE CAM97s. In other words, since the color matching process is performed using the device profile processed based on the conditions of the observation environment such as brightness and white selected by the user, the environment light is considered for the image read by the scanner. Color matching can be easily performed, and an image on which color matching according to ambient light has been performed can be displayed on a monitor.

[0090]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. Also,
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the operating system (OS) running on the computer based on the instructions of the program code.
It goes without saying that a case where the functions of the above-described embodiments are implemented by performing some or all of the actual processing, and the processing performs the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium has program codes corresponding to the flowcharts shown in FIGS. 13 to 16 (and, if necessary, FIGS. 17 and 18). Will be stored.

[0094]

As described above, according to the present invention,
Image processing for performing chromatic adaptation conversion under general viewing conditions can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an observation environment assumed by a CMS,

FIG. 2 is a diagram showing a processing system of CMS;

FIG. 3 is a diagram showing an example of the structure of a device profile.

FIG. 4 is a diagram showing an example of an actual observation environment in consideration of ambient light;

FIG. 5 is a diagram showing an example of a system configuration according to an embodiment of the present invention;

6 is a view showing an example of a user interface (UI) for setting viewing conditions provided by the scanner utility shown in FIG. 5;

FIG. 7 is a diagram showing values representing viewing conditions corresponding to each rank of each item in the user interface of the scanner utility shown in FIG. 6;

FIG. 8 is a diagram showing an example of a CMS process when environmental light is considered,

9A is a view showing observation condition parameters of the observation environment shown in FIG. 4;

FIG. 9B is a diagram showing a relationship between ambient light and observation condition parameters;

FIG. 10 is a diagram showing the contents of viewing condition tags included in optional tags of Inter Color Profile Format,

FIG. 11 is a diagram showing contents related to viewing conditions included in a private tag of Inter Color Profile Format,

FIG. 12 is a view showing profiles stored in a scanner profile storage unit and a monitor profile storage unit shown in FIG. 5;

FIG. 13 is a flowchart illustrating a color matching process according to the embodiment;

FIG. 14 is a flowchart illustrating an example of a procedure in which a rank of each item of a UI for setting an observation condition is selected;

FIG. 15 is a flowchart showing an example of a procedure for creating an observation condition tag and a private tag for a scanner and a monitor profile;

FIG. 16 is a flowchart showing an example of a procedure for setting an observation condition tag and a private tag created for a scanner and a monitor profile;

17 is a flowchart showing an example of a procedure for causing the CMM shown in FIG. 5 to execute a color matching process;

FIG. 18 is a diagram for explaining a forward conversion process of CIE CAM97s.

FIG. 19 is a diagram illustrating the inverse conversion processing of CIE CAM97s.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 AA11 BA25 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE18 5C077 LL19 MP08 PP32 PP36 PP37 SS05 5C079 HB01 HB05 HB12 LA23 LB02 MA17 NA03 PA05

Claims (8)

[Claims] 1. An image processing method for performing chromatic adaptation conversion on input image data according to a viewing condition, wherein a viewing condition is manually input, and a profile is processed in accordance with the input viewing condition. An image processing method, comprising: performing a color matching process in consideration of an input viewing condition based on a selected profile. 2. The image processing method according to claim 1, wherein the observation condition is information indicating brightness of illumination and white in an observation environment. 3. The image processing method according to claim 1, wherein the processing of the profile sets information on the input viewing condition as a tag. 4. The tag is an ICC (International Color).
4. The image processing method according to claim 3, wherein the tag is an optional tag and a private tag in a profile format defined by Consortium. 5. The image processing apparatus according to claim 1, wherein a user interface for responsively setting the viewing condition is used to input the viewing condition. Method. 6. The user interface according to claim 4, wherein at least one of the brightness and white of the illumination and the brightness and white of the monitor device can be responsively set. Image processing method. 7. The processing of a profile corresponding to the input viewing condition is performed with reference to a table indicating a correspondence between the responsively set environmental condition and an environmental condition value. An image processing method according to claim 4 or claim 5. 8. A recording medium on which is recorded a program code for image processing for performing chromatic adaptation conversion on input image data according to a viewing condition, wherein said program code includes at least a step of manually inputting a viewing condition. And a code of a step of processing a profile corresponding to the input viewing condition, and a code of a step of performing color matching processing in consideration of the input viewing condition based on the processed profile. A recording medium characterized by the above-mentioned.